| The pump station is a crucial hydraulic structure that plays a role in many applications.However,practical factors make its operating conditions complex.This complexity leads to the existence of various vortices in the water sump,resulting in non-uniform inflow at the pump inlet.In severe cases,a through-type suction vortex forms,significantly deteriorating the pump’s performance and affecting the pump station’s normal operation.Thus,it is necessary to explore deeply the mechanism of suction vortex formation and its impact on flow-passing components.In this paper,a centrifugal pump test platform with a sump was built,the shape and structure details of the evolution process of the suction vortex were analyzed,and the numerical simulation method of the suction vortex was established,and then the vortex area was analyzed,and the influence of the suction vortex on the suction pipe and the internal flow characteristics of the centrifugal pump was studied.Influence,summarize the law between the suction vortex and the energy characteristics of the pump,and analyze the pressure pulsation signal of the flow-passing parts.(1)Based on the built-up centrifugal pump full channel test platform,the suction vortex visualization test under different working conditions was carried out through high-speed camera technology.The unsteady numerical simulation results based on the VOF model were compared with the details of the shape and structure of the suction vortex captured by the test.,in-depth analysis of the evolution process of the suction vortex under different working conditions,to verify the reliability of the numerical simulation method and the feasibility of identifying the suction vortex by the fluid volume fraction,and thus establish a numerical simulation method for the suction vortex of the centrifugal pump device inlet.(2)Based on the established numerical simulation method,the distribution of the flow field in the vortex area in the inlet pool under the condition of the through-type suction vortex is analyzed.The formation mechanism of the through-suction vortex is analyzed based on vortex dynamics,and its influence on the flow field inside the draft tube is explored.The results show that the large velocity gradient is an important factor leading to the generation of the suction vortex,accompanied by the appearance of the low-pressure area.The mixing phenomenon of the flow velocity inside the draft tube makes the assumption of axial inflow of the impeller invalid.(3)The energy characteristics of the impeller is analyzed,and explore the influence of the air intake phenomenon caused by the penetrating suction vortex on the flow field characteristics inside the impeller.Analyze the time-frequency signal of the pressure fluctuation in the flow channel.As the suction vortex carries air into the impeller,its power decreases significantly,and the change trend is negatively correlated with the air content of the impeller.The proportion of pressure work of each part of the impeller decreases with the increase of the air content,resulting in an increase in flow loss.In addition,the generation of suction vortex has a great influence on the pressure pulsation signal of each measuring point inside the suction pipe and centrifugal pump,and the frequency domain components of each monitoring point become complicated after the generation of suction vortex. |
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